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Innate immunity Characteristics –Present at birth –Always present and available to provide rapid responses to disease –Does not involve specific recognition of a microbe –Acts on all microbes in the same way –No memory response

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Protection for the eye Tears are produced by the lacrimal gland Tears and their washing action helps keep the surface of the eye free from bacterial accumulation LYSOZYME is also found in tears and this enzyme has anti-bacterial action as well

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Fever Systemic response to injury Increase in body temperature as response to infection Shivering with fever is the results of a new higher set point for body temperature Fever is a defense against disease Fever may help to activate body defense mechanisms

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Antimicrobial Substances Complement Interferon

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Complement Defensive system of over 30 proteins that are made in the liver and circulate in the blood and tissues Activation of complement destroys microbes by lysis, inflammation, and phagocytosis Complement proteins act in a CASCADE, that is, one reaction triggers another

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Complement

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Interferon Classes of anti-viral proteins First discovered in the mid 1950’s Produced by cells such as lymphocytes, macrophages and fibroblasts AFTER viral stimulation - RNA viruses Interfere with viral multiplication

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Interferon Three classes of interferons –Alpha - leukocytes –Beta - fibroblasts –Gamma - lymphocytes (T cells) Produced after viral infection Induces near by cells to produce anti-viral to protect against the virus Currently produced by recombinant DNA technology

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Magic Bullet? Interferon has several limitation to its use –Short term effectiveness –Side effects –High concentrations toxic to heart, kidney, liver, bone marrow –Currently used to treat Hepatitis C –Used in Eastern Europe and Russia to treat colds and flu but this is widely accepted elsewhere